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Converting 2001 Passat

185K views 312 replies 53 participants last post by  etischer 
#1 · (Edited)
Noob to the site, figure i'd introduce myself.

I just bought a 2001 Passat with the intention of converting to electric. I have also bought the Siemens / Ford 3 phase motor. Im planning on upgrading a 2 horse 3 phase drive to 90 horse by running external IGBT's. The vfd drive can run on 300vdc or 230v by tapping into the DC bus. Im planning on using a rubber rotoflex coupling to couple the motor to the passat manual transmission. The rotoflex couplings are used alot on driveshafts in BMW's Land Rovers and Jags. I plan on making the adapter plate myself.

I bought the car yesterday for $1800. It has a siezed cam due to oil starvation.





About 24 hours later Im almost ready to pull the engine out



I'll keep you all posted with my progress. Any one out there run external IGBT's on a 3 phase motor controller? That's my biggest unknown right now.

Cheers
eric.
 
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#245 ·
Great thread, I read you page long before I found this. Thanks for that.
my contribution is that everything should be IP65.
this means the Charger and BMS needs to be redesigned.

the different voltage comes from using different IC chip from different silicon plates. We have to go through a Input inspection to make sure that all units are all the same batch. We then test that group for the ranges they will have so we can compensate.

The Charger should not be brute force but programmable with Thyristors so you can ramp up (input AC) and set the Raw DC level.
Also there should be not fans but the heat should be outside the Case using exterior Heat Sinks with a Wire cage guard.

The BMS should have all but the Heat producing Component in a IP65 enclosure with the heat production components mounted on an exter heat sink or PCB that has a wire cage to keep fingers away for heat and any thing over 30 Volts. Dry skin usually is 60 Volts before current flows.
 
#246 ·
I manually ramp the charger and it's in the trunk so technically it is IP66. Without fans, the charger's heat sink would probably be larger than would fit in the trunk, and would look a bit old school with a wire cage around it. I have thought about going water cooled. =)

Cell mounted BMS boards are optically isolated, so on each board there is no more than 4 volts. Getting the entire battery pack IP65 isn't really feasible, but the car does have a belly pan and fender liners, I've never seen water on top of the batteries. The cluster BMS boards are in the trunk, so they're IP66. The BMS I designed is actually IP67, but never got around to finishing it. It took up the entire trunk, Mini BMS works well enough for me. Here's a pic of my IP67 BMS, just like you describe with the heat producing part outside of the enclosure =)

 
#248 ·
Unlike you Have 300KW alternator where the transmission use to be off the Tbird 460. This kicks in when the Battery sages.
The batteries are charged off the Raw DC bus when in charge mode and then are boosted to Raw DC level when the Ultras Sage.

Believe it or not my 30ft Fageol is 1000 on the front and 1500 on the rear axle. Helps that is an all aluminum except the power train.
 
#254 ·




Finally got my Arduino wired into the dash. The tachometer motor is a stepper, so I'm using the Arduino and a stepper card to run it. I also replaced the dash clock with a 2 line LCD for displaying pack voltage and sag (lowest pack voltage from the last 30 seconds).
 
#255 ·
Cool!:D

I'll get to play with Arduino PLCs in my electronics class this semester. Can't wait.

Its always great to see the OEM look preserved as much as possible. Swapping gauges out is easy, what you're doing here is not.
 
#258 · (Edited)
The tach can hit 8k before reaching the end of travel. On the freeway I'm usually right at 4k which is right where peak power is (3rd gear). Accelerating on the freeway on ramp I'm in 2nd gear till about 7k before I shift to 3rd.

I guess I forgot to mention on this thread that I'm now running closed loop vector with encoder feedback! I have a bit more torque at low speed =) The throttle is much snappier too. If I do have a fault, I can now reset the controller on the fly, since the controller knows the motor rpm from the encoder, it can pick up where it left off. Previously I had to bring the motor to a stop before restarting.

I ended up installing an encoder on the motor, I had to design a bushing to fit inside the hollow motor shaft. The tone ring built into the motor was too coarse for my encoder card to read.





I chose an encoder disk and pickup because it was nearly impossible to find an encoder with bearings rated for 10k rpm.
 
#268 ·
I added a giant blower fan for cooling the trunk while charging.


It sucks air in though the existing trunk vent, then blows air across my DC-DC and charger when plugged into 115/240. If I have the A/C on, then it runs drawing air across the A/C compressor inverter heatsink.



It's rated 123 CFM, so it should exchange the air in the trunk every 30 seconds. We'll see how well it works when we start having those 100 degree days.
 
#269 ·
It is an fantabulously inspiring work!!!

I did not get one thing though. Do you use regen? If no, then skip the rest of my post. If yes, please see if you can address my Q.

I went through your page http://etischer.com/awdev/. I saw the connection diagram. I could not locate the regen path.

May be I am not seeing it because I do not still understand how it is supposed to be implemented.

When you tap the brake, is your inverter software actually changing the U, V, W phases so that the flux rotation direction actually reverses causing the motor to attempt rotating in reverse? And since the motor is hard coupled with wheels (via transmission, no clutch) and the wheel still rotates forward due to vehicle's momentum, the motor rotor is actually forcibly rotating opposite to the flux rotation direction. And this causes current to be generated to the U, V, W terminal, with the direction from motor to the inverter?

If the above is not correct, I will appreciate if you can educate me about what happens inside the motor when you tap the brake.

If the above is correct, I have follow up question. Now that there are 2 currents in opposite direction in each phase wire (connecting inverter and the motor terminals), the resulting current direction will be determined by the direction of stronger current. At the beginning (just after tapping the brake, when the flus direction reverses), since the car is still moving forward, the generated current overpowers the supplied current and the net current in the wires are flowing from motor towards inverter. But as the supplied current causes the motor to turn in reverse plus the effect of rolling resistance and road friction, the car slows down in the absence of accelarating torque and the generated current's strength diminishes. At some point the motor will come to standstill. The inverter should stop supplying current to motor, otherwise the motor will really start rotating in reverse causing the car to go in reverse. How is it done?

Now another important Q. When the current was flowing from motor towards inverter on all 3 phase wires, how is this current getting converted to DC and fed back to the traction battery pack? I mean those low side PWM circuitry and high side IGBTs can't play any role there, right? I did not find this path in your connection diagram.

I hope I am making some sense in my above questions. You can hit me if I am being absolutely silly.
 
#270 · (Edited)
In an induction motor, normal operation is when the rotor is lagging behind the rotating field in the stator. This is referred to as slip being >0 and produces torque which turns the motor. Torque is produced by the interaction of the magnetic field in the stator coils (caused by changing currents in the stator coils) and the induced magnetic field in the rotor coils. It is actually the physical orientation of the two fields at any given moment that is producing a torque.

If the rotor spins faster than the rotating stator field (slip < 0) then you get regen. Regen happens because the orientation of the two fields produces a negative torque. The energy stored in the magnetic field of the rotor now induces additional voltage (a back emf) in the stator which is greater that the battery voltage. This is where free wheeling diodes of each inverter IGBT are necessary. The back emf foward biases the diodes and allows the additional power to pass into the battery pack.

So no additional electronics in a three phase inverter are required.

Chris
 
#271 ·
Thanks a lot Chris.

I actually found a good thread that explains regen.

http://forums.mikeholt.com/showthread.php?t=101851 post#5.

The above article and your explanation together is making sense to me now. I was thinking that the VFD tries to revert the phase of U, V and W so that the flux starts moving in opp direction. But that is not true. The VFD slows down the frequency so much that the flux rotation speed becomes slower than the rotor speed so rotor leads the flux propagation. This results reversal of torque direction, which acts opposite to the vehicle inertia and slows the motor. I think I got the essence of it, right?

I also understand now that the generated AC current flows through the free wheeling diods to V+ terminal of the battery. But those are nearly sinusoid (with some ripple due to stator sloting) and 3 different phases. Since these are going through the diode, I guess only the positive portion of the sinusoid that is greater than (battery voltage + the forward biasing voltage) will make to the battery, correct? Still there is no smoothing. Does it not hurt the battery with such undulating voltage (when you superimpose upper half of three phase sinusoids, you get a undulating waveform), especially when it is Li-ion pack?
 
#274 ·
Guess he was a little ticked because you didn't let him in. However his lane wasn't ending so technically he had to yield to YOU (unless there was an emergency). If you closed the gap next to him, that's not breaking the law. He simply has to wait like everyone else.

You handled it well though. I like how he changed when he realized you had everything recorded.
 
#277 ·
In Washington Statethat is a ticket.
the car in front of you was signaling to pull over and you cut him off.
ticket for unsafe lane change.
I doubt any state has a law that the person signalling for a lane change has the right of way over the person already in that lane. Looked to me as if the cop intended to do the same maneuver that Eric did but was surprised by Eric already next to him. No ticket possible, and he knew it.
Eric, was he aware that he was being recorded? Also, do you always have a dash cam running?
 
#278 · (Edited)
This is the camera: Smarty BX1500+ HD 120

I have it set to always record, but you can set it up to only record when you press the record button or if it senses an impact, then it will save the previous 20 seconds and the next 20 seconds.

The software works really well, when you play back the video, it has other frames that show your car overlaid on google maps and has a graph of xyz acceleration.

I was pressing the record button while the officer was talking to me, the camera's right behind my mirror, so I'm sure he saw the camera.
 
#281 ·
Cops don't like to be passed no matter what speed they're going or lane they're in. At the front of every traffic jam there is guaranteed to be a copper doing 5 under.

It's especially funny the way he randomly yaps about it's crazy changing lanes like that to get on the highway (After seeing the cam and realizing he can't fabricate grounds for a ticket). Everyone has to get from the right lane to one of the left lanes, and it's just crazy to do that by changing lanes!
 
#284 ·
I don't notice any degradation from when they were new. Still sagging 10 volts per 100 amps. A little better in hot weather, a little worse (15 volts/100 amps) in cold.

I'm draining the pack exactly 50% once a day, 5 days a week. I don't pull more than 3C, my average draw is less than 1C. I think that's the key to a long life.

Forgot to mention we're installing solar too! Just enough solar to cover 50% of our usage, and lower our bill 80%.

 
#287 ·
Congrats Eric,
40k miles, that is some serious rolling.

Does the latch prevent you from closing the trunk while charging? Not sure what the climate is there, but would'nt it it allow rain water to enter the vehicle when its not all the way closed?

What about installing the Tesla port onto the charge cap/port of the vehicle so the trunk can be closed? Did I miss anything ? :confused:

//Steven
 
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